Endoscope

ABSTRACT

An endoscope especially adapted to inspect the bronchi of a human body or the like and having a forward end portion and a control housing connected to the forward end portion through an elongated flexible tube. The forward end portion can be flexed by the control from the control housing so that it can be smoothly inserted into the bronchi. The endoscope is provided with an observation optical system, an illuminating optical system and a control mechanism for flexing the forward end portion together with a pharmaceutical liquid injecting tube, a forceps conducting tube and a suction tube for sucking unwanted matter in the bronchi therefrom all in combination in compact form in the forward end portion without increasing the outer diameter of the forward end portion. To ensure positive and exact flexing of the forward end portion, a stay means made of a resilient, relatively stiff wire is provided longitudinally adjacent to the inner wall of the flexible tube section of the forward end portion. The both ends of the stay means are fixedly secured to the inner wall of the flexible tube section at its forward and rearward ends so that the stay means serves as a backbone to prevent the flexible tube section from being unduly contracted as a whole while the flexibility of the flexible tube section is maintained. To effect the bending of the flexible tube section, string means extend from the control mechanism through the elongated tube, the forward ends of the string means are secured to the inner wall of the flexible tube section so that the flexible tube section can be flexed by pulling the string means by the operation of the control mechanism.

SEARCH RQOM United States" l 3,610,231

suasnrun: FOR MISSING Xe [72] Inventors N g g Tflkahashi; PrimaryExaminer-Richard A. Gaudet TEN") Ouchi boih of y l p AssistantExaminerG, F. Dunne [2!] Appl. No. 7 A!t0rneyl(urt Kelman [22] FiledJuly 17,1968 [45] Patented Oct. 5, 1971 [73] Assignee Olympus OpticalCompany, Ltd. ABSTRACT: An endoscope especially adapted to inspect theTokyo, ]apan v bronchi of a human body or the like and having a forwardend [32] Priority July 21, 1967, Sept. 22, I967 portion and a controlhousing connected to the forward end [33] Japan portion through anelongated flexible tube. The forward end [3 l l 42/62666 and 42/81013portion can be flexed by the control from the control housing M g sothat it can be smoothly inserted into the bronchi. The en doscope isprovided with an observation optical system, an il- Iuminating opticalsystem and a control mechanism for flexing the forward end portiontogether with a pharmaceutical liquid injecting tube, a forcepsconducting tube and a suction tube for sucking unwanted matter in thebronchi therefrom all in combination in compact form in the forward endportion ENDOSCOPE 1 without increasing the outer diameter of the forwardend por- 4 Claims, 12 Drawing Figs. 0m

52 Us. Cl 128/6, To ensure Positive and exact flexing of the forward endP 95/11 EM tion, a stay means made of a resilient, relatively stiff wireis {51 1 Int. Cl A6lb 1/06 Pmvidsd longitudinally adjacent to the innerwall of the flexi- 123 4 5 6y ble tube section of the forward endportion. The both ends of 7 9 2; 95 1' 5; 138/120 the stay means arefixedly secured to the inner wall of the flex- I ible tube section atits forward and rearward ends so that the [56] References Cited staymeans serves as a backbone to prevent the flexible tube UMT STATESPATENTS section from being unduly contracted as a whole while theflexibility of the flexible tube section is maintained. To effect [50]Field of Search 2975'785 128/6 the bending of the flexible tube section,string means extend 3,253,524 5/1966 Ashizawa 95/11 from the controlmechanism through the elongated tube, the 3,4l7,745 12/1968 Sheldon128/6 forward ends of the string means are secured to the inner wallFOREIGN PATENTS of the flexible tube section so that the flexible tubesection can 830.639 W Gffial i n 2 be flexed by pulling the string meansby the operation of the 4,699 9/1905 France control mechanism.

PATENTEQ 001 51971 SHEET '1 BF 2 :55. vii-Elm INVENTORS. HRGfiStMGGTAKAHASPH Tutu owzHl PATENT-ETD um i n 3.610.231

SHEET 2 BF 2 INVENTOR MAGASH use TRKAH nsm T6113? 9 M H l ENDOSCOPEBACKGROUND OF THE INVENTION The present invention relates to a novel anduseful endoscope particularly adapted to be used for the inspection ofthe bronchi of a human body or the like having very narrow and tortuouspaths having different radii of curvature.

The present invention also relates to a novel and useful flexible tubeassembly adapted to be incorporated in the forward end portion of theendoscope of the type described above which is to be inserted into hebronchi smoothly without injuring the inner,wall of the bronchi.

It is well known that the diameters of the forward end portion andthe'elongated flexible tube of an endoscope for the inspection ofthebronchi ofa human body or the like must be very small such as thediameter of5.0 mm. or 5.5 mm. for the inspection of the deeper portionin the bronchi in comparison with commonly used endoscopes provided withthe forward end portion having the diameter of aboutl2 mm. for the in.-spection of the gullet or the stomach or the like.

On the other hand, it is desirable for an endoscope for the inspectionof the bronchi to-incorporate therein not only an observation opticalsystem such s an objective lens system and a fiber optical system butalso an illuminating optical system for illuminating the object to beinspected, a pharmaceutical liquid injection tube for injecting apharmaceutical liquid such as an anesthetic into the bronchi, a forcepsconducting tube for inserting the forceps into the bronchi so as tocollect the sample tissues to be inspected during the observation of theobject, a suction tube for sucking unwanted matter such as phlegm out ofthe bronchi, and string means for adjustably flexing the forward endportion of the endoscope in desired direction.

However, because of the very limited diameter of the forward end portionof the endoscope for the inspection of the bronchi, it has beenimpossible to incorporate all or most of the above-described variouselements compactly in the forward end portion of the endoscope while theoperation of each of the elements is kept satisfactory.

The reasons for the above facts are as follows. The suction tube forsucking the unwanted matter such as phlegm form the bronchi cannot bemade too small because the phlegm has a certain viscosity making itdifficult to smoothly suck the phlegm through the tube. If the wallthickness of the suction tube is made too thin in order to increase theinner diameter of the tube, then the tube tends to be easily collapsedin the region of the forward end portion of the endoscope when it isbent for the smooth insertion thereof into the bronchi thereby causingthe tube to be blocked.

Further, the mechanism for effecting the bending of the forward endportion of the endoscope requires relatively greater space therebypreventing the mechanism from being compactly incorporated in theforward end portion having a very limited diameter.

The present invention aims at avoiding the above disadvantages of theprior art and providing a novel and useful endoscope especially forinspecting the bronchi of a human body or the like and a novel anduseful flexible tube assembly to be incorporated in the forward endportion of the endoscope.

SUM MARY OF THE INVENTION An object of the present invention is toprovide a novel and useful endoscope for the inspection of the bronchiof a human body or the like which avoids the above-described disadvantages of the prior art endoscope.

Another object of the present invention is to provide a novel and usefulendoscope of the type described above in which an observation opticalsystem, an illuminating optical system and a mechanism including stringmeans for effecting the bending of the forward end portion of theendoscope for facilitating the smooth insertion thereof into the bronchiare compactly incorporated in the forward end portion of the endoscopehaving a very limited diameter such as 5.0 mm. or 5.5 mm.

together with a pharmaceutical liquid injection tube, a forcepsconducting tube and a suction tube for sucking unwanted matter such asphlegm form the bronchi into the which the forward end portion of theendoscope is inserted.

In order to smoothly insert the forward end portion of the endoscopeinto the bronchi, it is desired to permit the forward end portion of theendoscope to be bent not only in any desired direction but also todifferent radii of curvature so as to conform the flexure of the forwardend portion with different curvatures of the bronchi.

This is. accomplished by the significant feature of the presentinvention.

Therefore, further object of the present invention is to provide a noveland useful flexible tube assembly particularly adapted to beincorporated in the forward end portion of an ,endoscope which can bebent not only in any desired direction but also to different radii ofcurvature of the flexure of the forward end portion 'of the endoscope soas to facilitate the smooth insertion thereof into the bronchi havingnarrow and tortuous paths of different curvatures.

In principle, the forward end portion of the endoscope constructed inaccordance with the present invention comprises a flexible tube sectionsuch as a coarsely helically coiled strip forming a tube and two or morestring means with the forward ends thereof being secured to the forwardend of the flexible tube section and with the rearward ends thereofextending through the flexible tube section and being secured to acontrol mechanism in a control housing of the endoscope connected to theforward end portion through an elongated flexible tube through which thestring means extend so that the flexible tube section can be bent in anydesired direction by pulling the selected one or more of the stringmeans .by the selective operation of the control mechanism.

According to an important feature of the present invention, a stay meansis provided in the flexible tube section which is of a resilient,relatively stiff nature and extends longitudinally in the the flexibletube section adjacent to the inner wall thereof with the respective endsof the stay means being secured to the forward and rearward ends of theflexible tube section, respectively, so that the stay means serves as abackbone of the flexible tube section to prevent the flexible tubesection from being unduly contracted as a whole by the actuation of thestring means while the flexibility of the flexible tube section ismaintained. Thus, the flexible tube section can be bent in any desireddirection by selectively pulling one or more of the string means bydifferent amounts by means of the control mechanism.

In accordance with a further important feature of the present invention,a noncontractable pipe such as a tightly coiled wire forming a pipe isslidably fitted on each of the string means with the rearward end ofeach of the noncontractable pipes being flxed to stationary points inthe control housing while the forward ends thereof terminate in theregion of the flexible tube section and are secured to the inner wallthereof so that the movement of each of the string means relative to thenoncontractable pipe slidably fitted thereon at the rearward end thereofas given by the operation of the control mechanism is exactlytransmitted to the forward end portion of the string means relative tothe forward end of the noncontractable pipes, thereby permitting theflexible tube section to be flexed exactly as determined by theoperation of the control mechanism In accordance with a still furtherimportant feature of the present invention, only a pair of string meanseach having a noncontractable pipe slidably fitted thereon are providedtogether with a stay means in like manner as described above each of thestring means being arranged at opposite sides of the stay means insubstantially symmetrical relationship to each other in cross section ofthe flexible tube section with an angle being formed between two linespassing the center of the stay means and the respective string means incross section of the flexible tube section, the forward end of one ofthe noncontractable pipes terminating at a position intermediate thesmaller than the distance between the forward end of the flexil ble tubesection and the forward end of the other of the noncontractable pipes.Since thebending of the flexible tube section is effected in the portionof the flexible tube section which is contracted by the actuation of thestring means with the stay means sewing as a backbone of the flexibletube section, the

above-described construction in which the forward ends of thenoncontractable pipes are secured to the inner wall of the flexible tubesection at positions longitudinally shifted relative to each otherpermits the flexible tube section to be bent to different radius ofcurvature by selectively actuating either one of the string means.Further, by actuating both the string means selectively at differentdegrees, the flexible tube section 1 can be bent in any desireddirection and to varying radius of' curvature between the range asdetermined by pulling either one of the string means only:

Other objects and advantages of the present invention will be clear byreading the following description of the preferred embodiments of thepresent invention with reference to the accompanying drawingsillustrating the preferred embodiments of the present invention,

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a general side view showingthe endoscope constructed in accordance with one feature of the presentinvention;

FIG. 2 is a fragmentary side view of the endoscope shown in FIG. I asviewed from the right in FIG. 1;

FIG. 3 is a schematic view showing the various elements incorporated inthe endoscope shown in FIG. 1;

FIG. 4 is a schematic view showing the mechanism for effecting thebending of the forward end portion of the endoscope shown in FIG. I;

FIG. 5 is a plan view of the forward end plate provided at the forwardend of the forward end portion of the endoscope shown in FIG. I as seenfrom the rear side thereof;

FIG. 6 is a view showing the manner in which the forward end portion ofthe endoscope is bent in different directions by the selective actuationof the-string means incorporated in the mechanism for effectingthe'bending of the forward end portion ofthe endoscope;

FIG. 7 is a fragmentary view showing the forward end of the forcepsconducting tube around which a helically coiled strip is secured so asto prevent the forward end of the tube from being collapsed when thetube is bent;

FIG. 8 is a front end view showing the forward end plate provided withvarious elements for the operation of the endoscope;

FIG. 9 is a view showing the manner in which the forward end portion ofthe endoscope is inserted into the bronchi ofa human body;

FIG. I0 is a longitudinal sectional view of the forward end portion ofan endoscope constructed in accordance with another feature of thepresent invention;

FIG. II is a cross-sectional view taken along the line 11-11 in FIG. I0;and

FIG. 12 is a longitudinal sectional view taken along line 12-12 in FIG.10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now the presentinvention will be described in detail with reference to the drawings.

FIGS. I and 2 show an embodiment of the egdoscope constructed inaccordance with one feature of thepresai'fihvention. The endoscopecomprises a control housing I, an elongated flexible tube 2 and aforward end portion 3. The control housing 1 is connected to therearward end of the elongated flexible tube 2 around whichgripping-means 4 is provided for easy handling of the endoscope whilethe forward end of the elongated flexible tube 2 is connected to theforward end portion 3. The forward end portion 3 together with theelongated flexible tube 2 is adapted to be inserted into the bronchi ofa human body or the like so as to inspect the desired portion of thebronchi as described hereinbelow. As shown in FIG. 3, an objective lenssystem 5 is provided in a viewing window of the forward end portion 3 sothat the light from an object to be inspected is'received through theviewing window by the objective lens system 5 to thereby form an imageof the object in the forward end portion 3v An image transmittingoptical system 6 such as a fiber optical system extends from the forwardend portion 3 through the elongated flexible tube 2 to the controlhousing 1. The forward end of the image-transmitting fiber optical systern is located in the forwarde'iid portion Sin opposin g rel'at'fin'to the objective lens system 5 in alignment therewith so thatthe image of the object is focused on the forward end of theimage-transmitting optical system 6 thereby permitting the image to betransmitted through the image transmitting optical system 6 to therearward end thereof. An ocular means 7 is provided in the controlhousing I which is located in 0p posing relation to the rearward end ofthe image-transmitting optical system 6 in alignment therewith so thatthe image of the object thus transmitting to the rearward end of theimagetransmitting optical system 6 is viewed through the ocular means 7.An illuminating f ber optical system 8 extends from the forwarden'dpo'rtion 3 through the elongated flexible tube 2 to the controlhousing with the forward end thereof being in alignment with anilluminating window provided in the forward end portion 3 while therearward end thereof being in alignment with an illuminating windowprovided in the forward end portion 3 while the rearward end thereofterminates in a mounting 8a provided in the control housing I. A lightsource (not shown) may be connected to the mounting 8a preferablythrough a further fiber optical system provided with a mating connectingmember (not shown) for the mounting 88 at the outer end thereof so that,when the light source is connected to the mounting 8a and energized, thelight from the light source is received by the rearward end of theilluminating fiber optical system 8 and transmitted therethrough to theforward end thereof thereby permitting the thus transmitted light to beemitted from the forward end of the illuminating fiber optical system 8through the illuminating window in the forward end portion 3 so as toilluminate the image to be inspected. A forceps conducting tube 9 and apharmaceutical liquid injecting tube 10 also extend from the forward endof the forward end portion 3 through the elongated flexible tube 2 tothe control housing I with the rearward end of the forceps conductingtube 9 terminating at an opening 90 provided in the control housing 1while the rearward end of the pharmaceutical liquid injecting tube 10terminates at an opening 10a also provided in the control housing I.Thus, the forceps (not shown) are inserted from the opening 90 into theforceps conducting tube 9 therethrough so as to be projected from theforward end of the forward end portion 3 thereby permitting the forcepsto be manipulated from the exterior of the control housing 1 during theobservation of the object by means of the observation optical system inorder to collect the sample tissues necessary for the inspection fromthe bronchi into which the forward end portion 3 is inserted while thepharmaceutical liquid such as the anesthetic which is required for theinspection or the surgical operation of the bronchi can be supplied froma pharmaceutical liquid supply source (not shown) connected to theopening 10a through the pharmaceutical liquid injecting tube 10 to theforward end thercofso that the pharmaceutical liquid is injected intothe bronchi.

The forceps conducting tube 9 is provided with a suction tube I1branched from the forceps conducting tube 9 in the control housing I andterminating at an opening Ila which is provided in control housing 1.Means for closing the forceps conducting tube 9 such as a shutter blade12 is provided in the tube 9 at a position intermediate the rearwardendof the tube 9 and the position at which the suction tube 11 is branchedfrom the tube 9. A knob 12a for manually actuating the shutter blade 12is attached thereto and projects outwardly from the control housing 1 sothat the shutter blade 12 is opened and closed by the manual operationof the knob 12a. A suction device (not shown) may be connected to theopening 11a when unwanted matter such as phlegm in the bronchi should beremoved from the bronchi into which the forward end portion 3 of theendoscope is inserted. ln this case, the forceps are withdrawn from theendoscope and the shutter blade 12 is moved to its closed position bythe operation of the knob 120. Thus, when the suction device isoperated, the unwanted nlutter such as the phlegm in the bronchi can betaken out from the bronchi through the forceps conducting tube 9 and thesuction tube 11 by the sucking action of the suction device connected tothe opening 11a.

FIGS. 3 and 4 show one embodiment of the mechanism for controlling thebending of the forward end portion 3 of the endoscope. The forward endportion 3 comprises a forward endplate 14, a rearward end 15 such as anannular ring and a flexible tube section 13 such as a coarsely helicallycoiled steel strip forming a tubelike shape which flexible connected theforward end plate 14 and the rearward end 15. As shown in FIG. 8, theforward end plate 14 is provided with the viewing window with which theobjective lens system 5 in the forward end portion 3 is located inalignment, the illuminating fiber optical system 6 is located inalignment, opening connected to the forward end of the forcepsconducting tube 9 and an opening connected to the forward end of thepharmaceutical liquid injecting tube 10. As shown in FIG. 4, a staymeans 16 such as a resilient, relatively stiffwire extendslongitudinally along the inner wall of the flexible tube section 13adjacent thereto. The

forward end 160 of the stay means 16 is connected to the forward endplate 14 while the rearward end 16b of the stay means 16 is fixedlyconnected to the forward end of the elongated flexible tube 2 adjacentto the rearward end 15 of the forward end portion 3 so that the staymeans 16 serves as a backbone of the flexible tube section 13 of theforward end portion 3 to prevent the flexible tube section 13 from beingunduly contracted as a whole when it is subjected to an external forcetending to contract the flexible tube section 13 while it is allowed tobe bent thereby. A pair of strings 17, 18 extend from the forward endportion 3 through the elongated flexible tube 2 to the control housingl. The forward ends 17a 18a of the strings 17,18 are connected to theforward end plate 14 at positions opposite to each other with respect tothe position at which the forward end 16a of the stay means 16 isconnected to the forward end plate 14. Further string 19 extends fromthe forward end portion 3 through the elongated tube 2 to the controlhousing 1. The forward end 19a of the string 19 is connected to theforward end plate 14 at a position substantially diametrically oppositeto the position at which the forward end 160 of the stay means 16 isconnected to the forward end plate 14.

A control mechanism comprising two manually rotatable discs 20, 21having the common axis of rotation 22 is provided in the controlhousing 1. Either of the discs 20,21 may be provided with projections200 and/or 210 (only the projection 20a is shown) respectively, whichproject from the control housing 1 so as to be manually actuatedselectively so that either or both of the discs 20, 21 are rotated.Alternatively, the outer periphery of each of the discs 20,21 isprovided with a knurled surface a part of which projects from thecontrol housing 1 thereby permitting either or both ofthe discs 20,21 tobe manually rotated selectively by means of the knurled surfaces of thediscs 20, 21. The rearward ends 17!; 18b of thepair of strings 17, 18are connected to the disc 20 at positions diametrically opposite to eachother so that the manual rotation of the disc 20 in one direction causesone of the strings 17, 18 to be pulled while the other of the strings17, 18 is loosened and vice versa. The rearward end 1912 of the furtherstring 19 is connected to the disc 21 so that the string 19 is pulled bythe manual rotation of the disc 21 in one direction.

. Brake means 23, 24 such as friction pads may be provided for the discs20, 21, respectively so that the discs 20, 21 are frictionally held attheir adjusted positions. Noncontractable pipes 25, 26 and 27 such astightly coiled wires forming pipes extend through the elongated flexibletube 2 and are slidably fitted on the strings 17, 18 and 19,respectively, with the rearward ends 25a 26a and 27a thereof beingfixedly secured to stationary points in the control housing 1 while theforward ends of the pipes 25, 26 and 27 terminate at the rearward end 15of the forward end portion 3 of the endoscope and secured thereto, sothat the movement of the strings 17, 18 and 19 relative to thenoncontractable pipes 25, 26 and 27, respectively, as given at therespective rearward ends of the strings 17, 18 and 29 by the operationof the control mechanism can be exactly transmitted to the forward endsofthe strings 17, 18 and 19 relative to the respective forward ends ofpipes 25, 26 and 17, respectively. 1

In operation, the forward end portion 3 can be bent towar the right asviewed in FIGS. 5 and 6 by pulling only the string 19 by the manualoperation of the disc 21 in the direction of the arrow shown in FIG. 4.Under this condition, when the disc 20 is manually rotated in thedirection shown by the arrow in FIG. 4, the string 17 is pulled whilethe string 18 is loosened so that the forward end portion 3 is bent inthe direction shown by the arrow a in FIG. 6. When the disc 20 isrotated in the opposite direction, the forward end portion 3 is bent inthe direction, the forward end portion 3 is bent in the direction shownby the arrow bin FIG. 6.

It is apparent that the pulling of only of the string 17 or 18 causesthe forward end portion 3 to be bent further upwardly or downwardly asviewed in FIG. 6. Therefore, the forward end portion 3 can be bent inany direction within a predetermined solid angle determined by theflexure of the flexible tube section 13 by selectively actuating thestrings 17, 18 and 19 by means of the control mechanism. The stay means16 serves as a backbone to prevent the flexible section 13 from beingunduly contracted as a whole by the actuation of the strings 17, 18 and19 while the flexibility of the forward end portion 3 is maintained.

The brake means 23, 24 frictionally hold the discs 20, 21 in theiradjusted positions, respectively, thereby facilitating the inspection ofthe bronchi by the endoscope.

The forceps can be inserted into he forceps conducting tube 9 before orafter the forward end portion 3 is inserted in the bronchi for themanipulation of the forceps during the inspection of the object by meansof the observation optical system comprising the objective lens system5, the image-transmitting fiber optical system 6 and the ocular means 7.The pharmac'eutical liquid such as anesthetic can also be injected intothe bronchi through the pharmaceutical liquid injecting tube 10.Further, unwanted matter such as phlegm in the bronchi can be suckedtherefrom through the forceps conducting tube 9 and the suction tube 11by connecting the suction device to the opening of the suction tube 11after the forceps are withdrawn from the forceps conducting tube 9 andthe shutter blade 12 is moved to its closed position.

ln order to prevent the forward end of forceps conducting tube 9 frombeing collapsed by the bending of the forward end portion 3 so as topermit the unwanted matter to be sucked from the bronchi through theforceps conducting tube 9 without hindrance when it is used for removingthe unwanted matter from the bronchi, a thin-walled coarsely coiledstrip 28 such as helically wound steel strip may be provided around theportion adjacent to the forward end of the tube 9 in the region in theforward end portion 3 of the endoscope. The helically would strip 28 canbe fixedly embedded in the outer surface of the tube 9 by appropriatelyheating the tube 9 after the strip 28 is wound around the tube 9.

HO. 9 shows the manner how the forward end portion of the endoscope inaccordance with the present invention is inserted in the bronchi ofahuman body by the operation of the control mechanism of the endoscope asdescribed above.

The above-described construction of the endoscope in accordance with thepresent invention enables the various elements necessary for theinspection and surgical operation of the bronchi or the like to becompactly housed in the forward end portion of the endoscope having verysmall diameter such as 5.0 mm. or 5.5 mm. so that the forward endportion of the endoscope can be easily and smoothly inserted into thedeep internal portion of the bronchi by virtue of the convenientmanipulation afforded by the control mechanism of the present inventionwithout injuring the inner wall of the bronchi through which the forwardend portion of the endoscope in inserted and various operation necessaryfor the inspection and the surgical operation of the bronchi can befreely carried out.

FIGS. .0 to 12 show another embodiment of the flexible tube assemblyadapted to be incorporated in the forward end portion of the endoscopeconstructed in accordance with the present invention. 1

By this construction of the forward end portion of the en doscope, theforward end portion can be bent not only in any desired direction butalso to different radii of curvature by the selective actuation of thestring means connecting the flexible tube section of the forward endportion of the endoscope to the control mechanism in the control housingthrough the elongated flexible tube by the operation of the controlmechanism.

As shown in FIG. 10, the forward end portion of the endoscope comprisesa forward end section I and a flexible tube section II. A lens barrel 30mounting therein a cover glass 31 and an objective lens system 32 issecured in the forward end section I. A coarsely helically coiled strip33 forming a flexible tube such as that made of thin steel strip orsteel wire constitutes the flexible tube section II. The forward end ofthe helically coiled strip 33 is connected to he rearward end of thelens barrel 30 while the rearward end of the helically coiled strip 33is connected to the elongated flexible tube designated by the referencenumeral 111. As shown in FIG. 10, the imagetransmitting optical system34 such as a fiber optical system extends from the forward end section Ithrough the flexible tube section II and the elongated flexible tube Illtoward the control housing (not shown) as in the case of the embodimentshown in FIGS. 1 to 8. The forward end 34a of the fiber optical system34 is located in the lens barrel 30 behind the objective lens system 32spaced an appropriate distance therefrom in alignment therewith so thatan image of the object to be inspected is focused on the forward end 340by means of the objective lens system 32. Their'nage of the object istransmitted through the fiber optical system 34 to the rearward endthereof (not shown) provided in the control housing as in the case ofthe embodiment shown in FIGS. 1 to 8. Illuminating fiber optical systems35 (FIG. 11) also extend from the forward end section I through theflexible tube section II and the elongate flexible tube 111 to thecontrol housing. The rearward -ends of the illuminating fiber opticalsystems 35 are illuminated by a light source (not shown) so that thelight is transmitted through the fiber optical systems 35 to the forwardends thereof thereby permitting the light to be emitted thereof therebypermitting the light to be emitted therefrom so as to illuminate theobject as in the case of the embodiment shown in FIGS. 1 to 8. Theilluminating optical systems 35 can be replaced by lamp means located inthe forward end section I to which the electric power is suppliedthrough lead wire means extending from the control housing.

Other elements such as a forceps conducting tube also serving as asuction tube, a pharmaceutical liquid injection tube can also beincorporated in the endoscope of FIG. as in the case of the embodimentshown in FIGS. 1 to 8.

The outer peripheral surfaces of the forward end section 1, the flexibletube section II and the elongated flexible tube III are covered by apliant sheath 36 such that comprises of a plastic tube and a finetubular metallic netting fitted in the plastic tube or embedded thereinso as to watertightly keep the assembly.

Now the mechanism for flexing the forward end portion of the endoscopeshown in FIGS. 10 to 12 will be described in detail.

In the similar way to that shown in FIGS. 1 to 8, a staymeans 37 such asa resilient, relatively stiff steel wire is provided longitudinally inthe flexible tube section 11 adjacent to the inner wall thereof. Theforward end 370 of the stay means 37 is secured to the rearward end ofthe lens barrel 30 while the rearward end 37b of the stay means 37 issecured to the rearward end of the flexible tube section 11 so that theflexible tube section II is prevented from being unduly contracted as awhole by virtue of the provisions of the stay means 37 serving as abackbone of the flexible tube section 11 while the flexiblity of theflexible tube section 11 is maintained.

A pair of strings 38, 39 extend from the forward end section I throughthe flexible tube section II and the elongated flexible tube Illtowardthe control housing with the forward ends 380, 39a of the strings 38, 39being secured to the lens barrel 30 as shown. The location of thestrings 38, 39 is such that they are located opposite to each other withrespect to the stay means 37 spaced therefrom in cross section of theflexible tube section 11 as shown in FIG. 11 in substantiallysymmetrical relationship to each other with an angle A being formedbetween two lines connecting the center of the stay means 37 and thecenters of the respective strings 38, 39 in cross section of theflexible tube section II as shown in FIG. 11. The angle A may be eitheran obtuse angle or an acute angle, preferably an angle other than 180.The rearward ends ofthe strings 38, 39 are connected to a controlmechanism (not shown) provided in the control housing so that either oneor both of the strings 38, 39 can be selectively pulled by the operationof the control mechanism. I

As shown in FIG. 12, noncontractable pipes 40, 41 such as tightlyhelically coiled wires forming the pipes extend through the elongatedflexible tube Ill and are slidably fitted on the strings 38, 39,respectively. The rearward ends of the noncontractable pipes 40, 41 arefixedly secured to stationary points in the control housing (not shown)so that the movement of the strings 38, 39 relative to their pipes 40,41 at the rearward ends of the pipes 40, 41 as given by the operation ofthe control mechanism can be exactly transmitted to the forward endportions of the strings 38, 39 at the forward ends of the pipes 40, 41relative thereto. As shown in FIG. 12, the forward end 40a of the pipe40 terminates at a position intermediate forward and rearward ends ofthe flexible tube section II and secured to the inner wall of theflexible tube section II thereat while the forward end 41a of the pipe41 terminates at a position adjacent to the rearward end of the flexibletube section II and secured to the inner wall of the flexible tubesection II thereat. In other words, the string 38 extends freely withoutbeing covered by the pipe 40 the distance lla between the rearward endof the lens barrel 30 and the forward end 400 of the pipe 40 while thestring 39 extends freely without being covered by the pipe 41 thedistance 1117 which is greater than the distance Ila between therearward end of the lens barrel 30 and the forward end 410 of the pipe41. Thus, the actuation of the string 38 causes the length Ila of theflexible tube section II to be contracted while the actuation of thestring 39 causes the length llb of the flexible tube section II to becontracted.

.In operation, when only the string 38 is pulled by the opera tion ofthe control mechanism the length lla of the flexible tube section II isbent in the direction from the stay means 37 toward the string 38 incross section of the flexible tube section 11 only in the range of thelength Ila, while the stay means 37 serves as a backbone for theflexible tube sectionll to prevent it from being contracted as a wholeso that the radius tube section ll is made relatively large. When boththe strings 38, 39 are pulled simultaneously by different amounts, thenthe flexible tube section ll can be bent in any desired direction withinthe angle A as viewed in the cross section of the flexible tube sectionll with the radius of curvature of the flexure of the flexible tubesection ll being made intermediate the radii of curvature obtained whenthe respective strings 38 and 39 are pulled separately. 1

These features are extremely important in order to smoothly insert theforward end portion of the endoscope into the bronchi .having verynarrow tortuous paths without hindrance.

We claim:

1. An improved control mechanism for use in an endoscope which includesa control housing, an elongated flexible tube extending from saidhousing, a flexible tubular probe provided at the front end of said tubean objective lens system in said probe, ocular means in said housing,means for transmitting an image from said objective lens system throughsaid tube to said ocular means, a combined forceps conducting andsuction tube extending from said housing through said tube to saidprobe, a medication injecting tube extending from the housing throughsaid tube to the probe, and illuminating means provided at the probe,said improved control mechanism comprising a single resiliently bendablebut noncontractable stay extending longitudinally along only one side ofsaid tubular probe, said stay having a front end secured to the frontend of the probe and a rear end secured to said tube at the rear end ofthe probe so that the stay permits lateral bending of the probe in allradial planes but prevents longitudinal contraction thereof as a whole,and control means provided in said housing and including at least twostrings passing through said flexible tube into said probe, the frontends of said strings being secured to the front end of the probe atpoints which are spaced from the front end of said stay in such mannerthat the probe may be bent laterally in at least two different radialplanes by pulling of the respective strings.

2 The device as defined in claim I which is further characterized inthat said stay comprises a length of resiliently flexible wire.

3. The device as defined in claim 1 wherein said control means alsoincludes a third string passing through said flexible tube into saidprobe and having its front end secured t the front end of the probe at apoint spaced from the front ends of the first-mentioned strings and ofsaid stay.

4. The device as defined in claim I together with at least two flexiblebut noncontractable pipes secured in said housing and passing throughsaid flexible tube, said strings passing slidably through the respectivepipes, the front end of one of the pipes being secured at the rear endof said probe and the front end of the other pipe being securedintermediate the ends of the probe, whereby the probe may be laterallybent to different radii selectively along its whole length or along thelength of its front end portion by selective actuation ofsaid strings.

1. An improved control mechanism for use in an endoscope which includesa control housing, an elongated flexible tube extending from saidhousing, a flexible tubular probe provided at the front end of said tubean objective lens system in said probe, ocular means in said housing,means for transmitting an image from said objective lens system throughsaid tube to said ocular means, a combined forceps conducting andsuction tube extending from said housing through said tube to saidprobe, a medication injecting tube extending from the housing throughsaid tube to the probe, and illuminating means provided at the probe,said improved control mechanism comprising a single resiliently bendablebut noncontractable stay extending longitudinally along only one side ofsaid tubular probe, said stay having a front end secured to the frontend of the probe and a rear end secured to said tube at the rear end ofthe probe so that the stay permits lateral bending of the probe in allradial planes but prevents longitudinal contraction thereof as a whole,and control means provided in said housing and including at least twostrings passing through said flexible tube into said probe, the frontends of said strings being secured to the front end of the probe atpoints which are spaced from the front end of said stay in such mannerthat the probe may be bent laterally in at least two different radialplanes by pulling of the respective strings. CM,2Evice as defined inclaim 1 which is further characterized in that said stay comprises alength of resiliently flexible wire.
 3. The device as defined in claim 1wherein said control means also includes a third string passing throughsaid flexible tube into said probe and having its front end secured tthe front end of the probe at a point spaced from the front ends of thefirst-mentioned strings and of said stay.
 4. The device as defined inclaim 1 together with at least two flexible but noncontractable pipessecured in said housing and passing through said flexible tube, saidstrings passing slidably through the respective pipes, the front end ofone of the pipes being secured at the rear end of said probe and thefront end of the other pipe being secured intermediate the ends of theprobe, whereby the probe may be laterally bent to different radiiselectively along its whole length or along the length of its front endportion by selective actuation of said strings.